* {
  box-sizing: border-box;
}
*::before,
*::after {
  box-sizing: border-box;
}
#buttons {
  position: fixed;
  right: 0;
  top: 0;
  z-index: 10;
  display: flex;
  flex-direction: column;
  margin-top: 10px;
  margin-right: 10px;
}
#buttons > button {
  margin-bottom: 10px;
  padding: 4px 8px;
}
#demo1 {
  display: none;
}

#demo {
  position: fixed;
  height: 40vh;
  top: 0;
  left: 0;
  width: 100%;
  border: 1px solid red;
  overflow-y: auto;
}

#demo::-webkit-scrollbar {
  display: none;
}

#html {
  position: fixed;
  bottom: 5px;
  left: 0;
  width: 100%;
  height: 60vh;
}
